France, the strongest pro-China advocate, said "the embargo is anachronistic and must go" and showed "zero flexibility" on asking Beijing to make reforms in return for lifting the embargo, arguing that "China would not accept human rights conditionality."

Austria, Belgium, the Czech republic, Greece, Italy and the UK made more nuanced statements but were broadly-speaking in the French camp. The UK said only that diplomats should study implications for regional stability before making the move.

Denmark led the anti-China opposition, saying "Any decision to lift the arms embargo must be linked to specific Chinese steps on human rights."

Germany, the Netherlands and Sweden were closer to the Danish point of view.

Ireland, as the then EU presidency, tried to avoid taking sides. EU foreign ministers also tackled the subject later the same month. But with no clear outcome, the ban stayed in place.

Rockwell Schnabel, the US ambassador to the EU at the time, wrote in the cable that "all [EU countries] agree in principle that the embargo should be lifted if certain conditions are met." He added: "Our efforts have managed to slow down the momentum in favor of removing the arms embargo, but have not killed this idea outright."

EU diplomats expect talks on the ban, imposed in the wake of the 1989 Tiananmen Square massacre, to reopen in the run-up to the China-EU summit, due in autumn or winter this year.

Diplomatic sources told EUobserver the positions of two of the main players - France and the UK - have not changed, leaving Germany as perhaps the key swing country in the discussion.

The summit is due in a boom time in terms of China-EU economic relations - trade grew by more than 30 percent last year and China has bought billions of euros' worth of junk eurozone bonds during the crisis. But it is also due amid a severe crackdown on ethnic minority groups and dissidents, described as the worst in China's modern history by Human Rights Watch.

Ban or no ban, a second US cable leaked at the weekend noted that EU countries in 2003 sold China €400 million of "defence exports" and, later on, approved other sales of military grade submarine and radar technology.

A senior Irish diplomat, Dermot Gallagher, at the time "expressed surprise at this information, which, he said, would suggest that the embargo itself had been ineffective."